Plasma devices relate to the devices which are arranged to generate a gas plasma. Such gas plasma can be used, for instance, in surgery for the purpose of causing destruction (dissection) and/or coagulation of biological tissues.
As a rule, such plasma devices are formed with a long and narrow end or the like which can easily be applied to a desired area that is to be treated, such as bleeding tissue. At the tip of the device, a gas plasma is present, the high temperature of which allows treatment of the tissue adjacent to the tip.
WO 2004/030551 (Suslov) discloses a plasma surgical device according to prior art. This device comprises a plasma-generating system with an anode, a cathode and a gas supply channel for supplying gas to the plasma-generating system. Moreover the plasma-generating system comprises a number of electrodes which are arranged between said cathode and anode. A housing of an electrically conductive material which is connected to the anode encloses the plasma-generating system and forms the gas supply channel.
Owing to the recent developments in surgical technology, that referred to as laparoscopic (keyhole) surgery is being used more often. This implies, for example, a greater need for devices with small dimensions to allow accessibility without extensive surgery. Small instruments are also advantageous in surgical operation to achieve good accuracy.
When making plasma devices with small dimensions, there is often a risk that material adjacent to the cathode is heated to high temperatures due to the temperature of the cathode, which in some cases may exceed 3000° C. At these temperatures there is a risk that material adjacent to the cathode is degraded and contaminates the gas plasma. Contaminated gas plasma may, for instance, introduce undesirable particles into the surgical area and may be injurious to a patient who is being treated.
Thus, there is a need for improved plasma devices, in particular plasma devices with small dimensions which can produce a high temperature plasma.